Designing a Dungeon

From OSE SRD

1. Choose the Setting

Decide on the basic form and structure of the dungeon (the table below may be used) and begin to consider ideas for the main rooms or areas.

Dungeon Setting

d6 Setting
1
Crypt or tomb complex
2
Natural caverns
3
Settlement (e.g. stronghold, city)
4
Subterranean delving (e.g. mine)
5
Temple
6
Tower or fortification

2. Choose Monsters

Based on the selected adventure scenario and dungeon setting, decide what types of monsters inhabit the dungeon, choosing from any monster books that are available, creating new monsters specially for the dungeon, or tailoring standard monsters to the location.

3. Map the Dungeon

Overall shape: The structure of the rooms and connecting passages will be determined by the dungeon setting (e.g. rough cavern walls, carefully laid-out defensive structures, etc.).

Mapping scale: Typically, dungeon maps are drawn on graph paper with a scale of 10’ per square. (Larger or smaller scales may be used as appropriate.)

Numbering: Give each area (e.g. room or cave) of the dungeon a number, so that the area on the map can easily be cross-referenced with the description of its contents (see step 4).

4. Stock the Dungeon

Make notes describing each area on the map that was given a number. Monsters or areas that play an important role in the adventure should be noted first. Areas of less importance may then be stocked (using the guidelines to the right if desired).

Important details: Monsters (including the possibility of patrols in the area), traps, tricks, treasures, or special magical effects that are present should be noted.

Secondary details: Additional descriptive details for each area may also be noted: furnishings, everyday items, smells, sounds, lights, etc.

Dungeon Levels

Dungeons often consist of a series of deeper and deeper floors—known as levels—accessible by stairways, trap doors, chutes, pits, etc. PCs enter the 1st level of a dungeon initially and may discover entrances to deeper levels.

Danger and Reward

Generally, the level of danger and the amount of treasure in a dungeon should be suitable to the level of the PCs.

It is usual for lower levels of the dungeon to have greater risks and rewards. Normally, 1 HD monsters live in the 1st level of a dungeon, 2 HD monsters in the 2nd level, and so on.

Unguarded Treasure

Treasure is usually guarded by monsters or traps, but sometimes an unguarded cache of loot may be found.

Experienced players: When designing dungeons for experienced players, the referee should consider placing only very few completely unguarded treasures.

Deep dungeon levels: The referee may wish to not place any unguarded treasures in the 9th or deeper dungeon levels.

Random Room Stocking

Random Dungeon Room Contents

d6 Contents Chance of Treasure
1–2 Empty 1-in-6
3–4 Monster 3-in-6
5 Special None
6 Trap 2-in-6


Monsters: May be selected by hand or rolled on an encounter table.

Specials: Weird or magical features of an area, including tricks or puzzles.

Traps: If treasure is present, the trap may be set so that it is triggered when the treasure is tampered with (a treasure trap). Otherwise, the trap may be triggered by simply entering the room or a certain area of it (a room trap).

Treasure: If a monster is in the room, roll the treasure type indicated in its description. Otherwise, the treasure depends on the dungeon level (see below).

Example Room Traps

  1. Falling block: Inflicts 1d10 damage (save versus petrification to avoid).
  2. Gas: Poisonous gas fills the room (save versus poison or die).
  3. Mist: Harmless; looks like poison gas.
  4. Pit: Opens up beneath characters’ feet, inflicting falling damage on any who fall in (see Falling).
  5. Scything blade: Swings from the ceiling, attacking for 1d8 damage.
  6. Slide: Opens up beneath characters’ feet, sending them to a lower level.

Example Treasure Traps

  1. Darts: 1d6 spring-loaded darts fire at the character, doing 1d4 damage each.
  2. Flash of light: Causes blindness for 1d8 turns (save versus spells).
  3. Hidden monster: e.g. a snake. Released when the treasure is disturbed.
  4. Illusion: Typically of a monster. The monster has AC 9 [10] and vanishes if hit in combat. Its attacks do not inflict real damage: a PC who appears to die just falls unconscious for 1d4 turns.
  5. Spray: A mysterious liquid covers the character. Monsters are attracted to the smell: the chance of wandering monsters is doubled for 1d6 hours.
  6. Sprung needle: A needle coated with poison jabs out (save vs poison or die).

Example Specials

  1. Alarms: Entry alarm that attracts nearby guardians.
  2. Animating objects: Inanimate objects that attack if disturbed.
  3. Falling blocks: Stone block falls to prevent passage.
  4. Illusions: Illusionary passages, doors, or stairways.
  5. Shifting architecture: Doors lock and the room rotates, rises, or falls.
  6. Strange waters: Pool or fountain with weird, magical effects.
  7. Teleports: Magical portal or teleporter to another area of the dungeon.
  8. Trapdoors: Leading to a hidden area.
  9. Voices: Walls or architectural features speak or moan (e.g. a talking statue).

Treasure

Level 1: 1d6 × 100sp; 50%: 1d6 × 10gp; 5%: 1d6 gems; 2%: 1d6 pieces of jewellery; 2%: 1 magic item.

Level 2–3: 1d12 × 100sp; 50%: 1d6 × 100gp; 10%: 1d6 gems; 5%: 1d6 pieces of jewellery; 8%: 1 magic item.

Level 4–5: 1d6 × 1,000sp; 1d6 × 200gp; 20%: 1d6 gems; 10%: 1d6 pieces of jewellery; 10%: 1 magic item.

Level 6–7: 1d6 × 2,000sp; 1d6 × 500gp; 30%: 1d6 gems; 15%: 1d6 pieces of jewellery; 15%: 1 magic item.

Level 8–9: 1d6 × 5,000sp; 1d6 × 1,000gp; 40%: 1d12 gems; 20%: 1d12 pieces of jewellery; 20%: 1 magic item.